html{
  font-family: STXihei, "华文细黑", "Microsoft YaHei", "微软雅黑";
}
.main{
  box-sizing: border-box;
  width: 100%;
  max-width: 1200px;
  padding: 64px 16px 0;
  margin: 10px auto 0;
  background: #fff;
  box-shadow:  0 0 2px #ccc;
}

@media screen and (max-width:778px) {
  .main{
    width: 100%;
  }
}